Fungi Isolated from the Affected Tea Plant by the New Die-back and Canker Disease and their Pathogenicities

Abstract

The causal fungi of tea die-back and canker disease were searched for 3 years since 1959, and the following more than 30 species of fungi were isolated:Aspergillus sp.+, Botrytis sp.+, Chaetophoma sp.+, Colletotrichum sp.+, Diplodia sp., Fusarium spp., Leptosphaeria sp.+, Macrophoma sp.+, Nectria sp., Pestalotia spp*., Phomopsis sp.+, Pullularia sp.+, Verticillium sp.+, unidentified fungi A-a*, B, Q+, R+, S+, and about 10 different unidentified fungi+ The * fungi were common and + fungi rare. Samples were collected from Saitama, Shizuoka, Aichi, Mie, Nara, Miyazaki and Kagosbima prefectures.There was no definite relation between the kinds of fungi and the symptoms of disease, varieties and ages of tea plant, locations of sampling, and brownness of specimen.Comprehensive inoculations, using different techniques of wounding and sevetal types of inoculum, were given on the shoot cuttings, sand cultured young seedlings in the laboratory, and on the different portions of tea plant in the field at various times of year.Chaetophoma sp., Diplodia sp., Leptosphaeria sp., Nectria sp., Phomopsis sp., unidentified. fungi B, Q, R and S occasionally caused somewhat browning around the inoculated portions, but none of the fungi tested showed pathogenicity on the stem of matured plant.It was remarkable that Pestalotia spp. and unidentified fungus A-a were not pathogenic at all, . though they were found very frequently.It seems that some of these fungi may be pathogenic, but likely not be the cause of the disease, and the physiological conditions of the host may play a role in the outbreak of disease.